Did you know that a lactating cow drinks up to 190 litres a day? One cow. One bathtub full of water.
This may be common knowledge to some, but it’s only just struck home for me. Shocked, I wanted to know a bit more.
This is what I found out:
We have about 3.85 million dairy cows in New Zealand. Using a lower, and hopefully more accurate statistic of 100 litres a day per lactating cow feeding on grassland, our dairy herd drinks up to 385 million litres of water per day during the milking season (up to 300 days of the year). That doesn’t count other water spent in irrigation, cleaning out of cow sheds, and processing of milk.
The national dairy output is 13.1 billion litres of milk per year (maybe 14 billion now). If my math is right, that means approx 3,400 litres of milk is produced for every 36,500 litres of water drunk.
Of course, the next question for is, how do sheep compare in water requirements? The answer for is, for ewes with lambs – 10 litres of water per day. In hot weather, merino sheep apparently drink 20 per cent less water than British breed sheep. I don’t have statistics on water usage for processing wool into yarn. After scouring, the carding and spinning processes are not water dependent. Although dyeing would take up more water. I wasn’t able to find out any more facts about this.
New Zealanders consume about 760 litres per family of four per day(!), which translates to approx 190 litres per person. I’ve seen other stats that say 160 litres per person. Only 2% of that is used for drinking. We might not drink as much as a cow, but we do use a lot of water for other ‘stuff’. Here’s where it typically goes. I don’t feel quite so grumpy at the cows now, but… how can I reduce my water usage?
We can save water by using the half-flush in toilets; water efficient washing machines; not letting the water run when brushing teeth or washing the car; showering, not bathing, and using water-efficient shower heads; and drip feeding plants (or collecting rain to water plants and wash cars). Fix leaks.
Interesting. And thought provoking. But I’m still feeling guilty about drinking milk.